Egr

[cjdavid]

probably a thread that has already been talked about, I need some info on keeping the EGR closed. How does one go about this? Will it send a check engine code and lite on? Is there any bad affects from doing this, as in where does the hot exhaust go to if not allowed to be open?

 

[HotRodKid]

why do you want to keep the egr closed ?

and theres 2 ways of doing it, make a block off plate between the manifolds and the egr tube, and shut it off with tuning software / lpm

bad effects: reduces milage

and the exhaust stays in the exhaust if the egr doesnt open

 

[luigisho]

You may have to weld or braze it closed.

The exhaust gas recirculation valve will not recirculate-- just shoot out the exhaust.

 

[cjdavid]

maybe i should ask for the pros and cons of doing any mods to the EGR either keeping it opened or closed.

 

[naval-avi8or]

Best way would be to get an Xcal and a tune to shut if off that way you will not get an MIL (CEL) and code. This would also allow you to flash the PCM when you would want to drive with the EGR off and then reflash back to normal for every day driving.

PROS: I don't know
CONS: Reduced fuel Milage, Won't pass any emission test and probably some others.

 

[HotRodKid]

keping it open:

Pro's - none ...unless you just dont feel like replacing a defective EGR
Cons:
- manifold vacuum at idle goes to shit,
- car probably wont even idle because its a massive vacuum leak which is feeding the engine an inert gas
- did u want vacuum assisted brakes ? yea, those are gone now ...

keeping it closed

Pro's: - the intake doesnt see as much heat
con's: less MPG while cruising on the highway

HOW AN EGR WORKS (aka, what it realy does)

its closed at idle
its closed while accellerating

the only time its open is when your cruising at a constant speed

what its there for: while cruising, the egr opens, which allows exhaust to enter the combustion chambers. exhaust gas obviously doesnt burn. this has the effect of reducing the engines displacement

less fresh air is needed
less fuel is needed
the ecu is able to adjust the timing for even better mileage

when you decide to accelerate, the ECU automaticly closes the egr so you can have full HP again

 

[cjdavid]

enough said! since i am working on more mpg we shall leave it alone. thanks guys!

 

[HotRodKid]

do you have to pass a sniffer test or anything like that ?

lean out the ARF for cruising speeds, something like 16.5: is the "maximum economy" air fuel ratio for an engine (might eat your converters if you still have them)

contrary to popular beleif, 14.7 isnt the best for mileage, its the best for emissions

 

[Silvapain]

Another Con to the EGR being open is that it leaves a nice thick film of carbon all over the intake and valves. Also, the EGR valve opens during deceleration. Another purpose of the EGR system is to reduce combustion chamber temperatures. Otherwise, the HotRodKid has it dead on.

 

[me6894]

the point of the EGR valve is to open to allow exhaust gases into the engine to LOWER combustion chambers... that being said if you take that away and dont have some way of making up for it (tuning or something), you run the risk of pre-ignition or detonation. i would recommend not messing with it because even if you do take it off, you probably wont see much of a gain

 

[Silvapain]

the point of the EGR valve is to open to allow exhaust gases into the engine to LOWER combustion chambers... that being said if you take that away and dont have some way of making up for it (tuning or something), you run the risk of pre-ignition or detonation. i would recommend not messing with it because even if you do take it off, you probably wont see much of a gain

I already said that. Read the post before you.

There's already a way built into the SHO to take care of detonation - it's called the knock sensors. The PCM will retard timing automatically if the sensors detect knock.

The main reason I would remove the EGR system is to keep carbon out of my intake and heads. I know first-hand what carbon build-up can do to an engine.

 

[SHOZ123]

And the EGR adds a lot of heat to the intake manifold. Without the EGR the intake manifold was ~125F with the EGR it was over 170F this was on a 90F day on the highway.

 

[HotRodKid]

on the highway being the key words

intake heat helps vaporize the fuel, as the injectors are often spraying on closed valves

theres NOTHING wrong with a hot intake, unless your doing roll races or at a track day (but the egr isnt open when your driving hard anyways)

 

[SHOZ123]

Seeing as the fuel sprays almost entirely on the valve or the area in the head near the valve I see not where any heat in the intake above the FI would do any good at all. It will only limit total O2 volume. The colder the better.

Not to mention the FI atomizes the spray of fuel in the first place.

 

[projectSHO89]

The whole PURPOSE of the EGR system has been missed in this whole discussion.

It is there specifically to reduce the oxides of notrogen (NOx) that are created by high combustion temps. Recirculating the exhaust gas decreases the temps which brings the NOx levels back down. It is there specifically and only for pollution control.

It only functions during steady state driving. It is NEVER commanded at either idle or accelleration.

HRK's description is pretty darned good....

Steve

 

[SHOZ123]

Well to answer the original question the easiest way is to pull the vacuum hose off and plug it or disconnect the vacuum solenoid electrical connector. This way it is easily reversible if needed for emission testing. It will set a code unless it is blocked by programming.

 

[stephen newberg]

The whole PURPOSE of the EGR system has been missed in this whole discussion.

It is there specifically to reduce the oxides of notrogen (NOx) that are created by high combustion temps. Recirculating the exhaust gas decreases the temps which brings the NOx levels back down. It is there specifically and only for pollution control.

Thank you, Steve. The answer is not to disconnect your system, even in a way so as to be able to re-connect it for an emissions test. The answer is to have the ERG working properly so it can do what it was designed to do and for you to have as legal and non-polluting a car as possible.

pax, smn

 

[SHOZ123]

If they don't test what's illegal????

 

[Motoman991]

Thank you, Steve. The answer is not to disconnect your system, even in a way so as to be able to re-connect it for an emissions test. The answer is to have the ERG working properly so it can do what it was designed to do and for you to have as legal and non-polluting a car as possible.

pax, smn

Tree hugger

 

[stephen newberg]

LOL. You know better than that, Paul.

There is a Federal law. Just because there is not a State law does not mean the Federal law is not there.

And I have a big chain saw 'cause I like cutting down trees.

pax, smn